Have they also removed the option to set an iCloud ID / Apple ID on a user account as well? I was talking to Apple Care and the senior advisor said that it should still be a feature in OS X 10.11.4 and that it was on her laptop. For the account that I already had created it presented a dialog asking me to change my iCloud password when I clicked on reset password maybe because it was created pre OS X 10.11.4.
– Brett BestMar 23 '16 at 6:01

I just did a clean install and it let me use my iCloud account. However I still can't do it for a second account.
– Brett BestMar 23 '16 at 7:06

1

If you right click on a username you can go to Advanced settings. You can set an Apple ID there. But for some reason they removed the use iCloud password feature.
– stefanbcMar 23 '16 at 10:55

stefanbc is correct here. If you want to add an iCloud account to a user just create the user and sign in to iCloud in iCloud settings. I believe this does the same thing as changing the iCloud account in Advanced settings
– rjsmithMar 24 '16 at 18:12